Ophthalmology (Eye & Ear Hospital) - Research Publications
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ItemNo Preview AvailableKeratoconus International Consortium (KIC)- advancing keratoconus research(BMC, 2023-07-27)CLINICAL RELEVANCE: The Keratoconus International Consortium (KIC) will allow better understanding of keratoconus. BACKGROUND: Keratoconus is a disorder characterised by corneal elevation and thinning, leading to reduced vision. The current gaps in understanding of this disease will be discussed and the need for a multi-pronged and multi-centre engagement to enhance our understanding of keratoconus will be highlighted. DESIGN: KIC has been established to address the gaps in our understanding of keratoconus with the aim of collecting baseline as well as longitudinal data on several fields. PARTICIPANTS: Keratoconus and control (no corneal condition) subjects from different sites globally will be recruited in the study. METHODS: KIC collects data using an online, secure database, which enables standardised data collection at member sites. Data fields collected include medical history, clinical features, quality of life and economic burden questionnaires and possible genetic sample collection from patients of different ethnicities across different geographical locations. RESULTS: There are currently 40 Australian and international clinics or hospital departments who have joined the KIC. Baseline data has so far been collected on 1130 keratoconus patients and indicates a median age of 29.70 years with 61% being male. A total of 15.3% report a positive family history of keratoconus and 57.7% self-report a history of frequent eye rubbing. CONCLUSION: The strength of this consortium is its international, collaborative design and use of a common data collection tool. Inclusion and analyses of cross-sectional and longitudinal data will help answer many questions that remain in keratoconus, including factors affecting progression and treatment outcomes.
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ItemNo Preview AvailableComplications of laser-assisted in situ keratomileusis(WOLTERS KLUWER MEDKNOW PUBLICATIONS, 2021-07)Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.
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ItemVolcano explosion in the eye: Expulsive choroidal haemorrhage.(Medknow, 2022-02)BACKGROUND: This video shows the dreaded complication of expulsive suprachoroidal haemorrhage in a penetrating keratoplasty . It teaches the various measures that help in preventing and managing the challenge peri-operatively. PURPOSE: This video is intended to sensitize the corneal surgeons about this rare complication using real-time surgical video and prepare them to face this challenge by demonstrating the preventive and mitigating strategies. SYNOPSIS: A patient who was suitably taken up for an autokeratoplasty had expulsive choroidal haemorrhage in the non-seeing eye. This complication was managed using glycerin-preserved donor corneal button. Further, the video discusses various pre-operative and intra-operative optimizations to avoid such a complication and mitigate the damage caused by it, should it ever happen during a surgery. HIGHLIGHTS: Expulsive choroidal haemorrhage can be a traumatizing event and one must be mentally prepared to manage it. Pre-operative high-risk factors should always be managed and intra-operative maneuvers performed to prevent the complication, as shown in the video. VIDEO LINK: https://youtu.be/s_ImBugPELw.
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Item"Chopper Shield" Technique to Protect Corneal Endothelium During Phacoemulsification Surgery for Rock Hard Cataracts(DOVE MEDICAL PRESS LTD, 2021)PURPOSE: To describe an innovative technique of using a chopper as a shield for preventing mechanical corneal endothelial trauma that can occur during the phacoemulsification of brunescent cataracts. METHODS: This prospective study included patients with hard cataracts (grade nuclear opalescence 4 and above on LOCS III) who underwent phacoemulsification surgery. The chopper shield technique was performed in 48 eyes of 44 patients. The technique entailed placing the chopper horizontally as a shield anterior to the emulsifying nuclear fragment between the phaco tip and corneal endothelium to prevent nucleus fragments from coming into contact with the corneal endothelium. Outcome measures included cumulative dissipated energy (CDE), corneal edema (day one), CCT (assessed at one day, one week, and one month), and endothelial cell density assessed at three months. RESULTS: Of the 48 eyes included in the study, 23 were males and 25 were females (mean age: 70.02±5.98years). Preoperatively, mean central corneal thickness (CCT) was 529.62±21.70 microns, and endothelial cell counts were 2258.76±182.22 cells per mm2. Postoperatively on day one, CCT increased to 563.93±24.53 microns, a 6.47% increase from preoperative central corneal thickness. CCT became 534.83±22.64 microns on postoperative day seven, a 0.98% increase from preoperative CCT. Endothelial cell loss was 6.77% at three months from the day of surgery. CONCLUSION: The chopper shield technique offers continuous protection to the corneal endothelium by minimizing endothelial cell loss during phacoemulsification of dense nuclear cataracts.
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ItemA Comparison of Refractive Accuracy Between Conventional and Femtosecond Laser Cataract Surgery Techniques Using Modern IOL Formulas(DOVE MEDICAL PRESS LTD, 2021)PURPOSE: To compare the refractive outcome prediction accuracy between conventional (CCS) and femtosecond laser assisted (FLACS) cataract surgery techniques using optimized lens constants for modern intraocular lens (IOL) formulas. PATIENTS AND METHODS: Our retrospective, comparative, interventional case series, compared data from 196 eyes undergoing CCS and 456 eyes undergoing FLACS with Acrysof IOL (Alcon laboratories, Inc) implantation. After optimizing IOL constants, the predicted refractive outcome was calculated for all formulas for each case. This was compared to the actual refractive outcome to provide the prediction error. The performance of CCS and FLACS was compared by the absolute prediction error and percentage of eyes within 0.25D, 0.5D and 1.0D of anticipated refractive outcome. RESULTS: There was no statistically significant difference in median absolute error between the CCS and LACS groups for the Kane (0.256, 0.236; p=0.389), SRK T (0.298, 0.302, p=0.910), Holladay (0.312, 0.275; p=0.090), Hoffer Q (0.314, 0.289; p=0.330), Haigis (0.309, 0.258; p=0.177), Barrett Universal 2(0.250, 0.250; p=0.866), Holladay 2 (0.250, 0.258; p=0.860) and Olsen (0.260, 0.255; p=0.570) formulas. Similarly, there was no consistent difference between the two techniques for percentage of patients within 0.25, 0.50 and 1.0D of predicted refractive outcome for each formula. CONCLUSION: There was no difference in refractive outcome prediction accuracy between the CCS and FLACS techniques.
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ItemNo Preview AvailableA retrospective study of the indications and outcomes of capsular tension ring insertion during cataract surgery at a tertiary teaching hospital.(Informa UK Limited, 2013)BACKGROUND: The purpose was to determine preoperative indications, intraoperative procedures, and outcomes of capsular tension ring (CTR) insertion during cataract surgery. METHODS: A review of all patients undergoing cataract surgery with insertion of a CTR between July 2000 and June 2010 was conducted at The Royal Victorian Eye and Ear Hospital, a large tertiary teaching hospital in Victoria, Australia. Information relating to each patient's demographic details, preoperative assessment, surgical procedure, and postoperative assessment were obtained. RESULTS: Eighty-four eyes of 82 patients were included in this study. The main indications for CTR insertion were previous trauma, pseudoexfoliation syndrome, and mature cataracts. Twenty-one eyes (25.0%) did not have any obvious preoperative indication. A posterior capsule tear was the most common intraoperative complication (3.6%). An intraocular lens was successfully implanted in the bag in 72 eyes (85.7%). Postoperatively, the most common complications were a decentered intraocular lens (8.3%) and persistent corneal edema (6.0%). Overall, 61 eyes (72.6%) had better postoperative visual acuity compared with preoperative acuity, with 67 patients (79.8%) achieving vision of 20/40 or better. CONCLUSION: For the majority of cases, CTR use in complex cataract surgeries is associated with improved postoperative outcomes. CTR implantation is most commonly required in patients with known risk factors for zonular instability.
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ItemNo Preview AvailableDevelopment of Novel In Silico Model to Predict Corneal Permeability for Congeneric Drugs: A QSPR Approach(HINDAWI LTD, 2011)This study was undertaken to determine in vivo permeability coefficients for fluoroquinolones and to assess its correlation with the permeability derived using reported models in the literature. Further, the aim was to develop novel QSPR model to predict corneal permeability for fluoroquinolones and test its suitability on other training sets. The in vivo permeability coefficient was determined using cassette dosing (N-in-One) approach for nine fluoroquinolones (norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, sparfloxacin, pefloxacin, gatifloxacin, and moxifloxacin) in rabbits. The correlation between corneal permeability derived using in vivo studies with that derived from reported models was determined. Novel QSPR-based model was developed using in vivo corneal permeability along with other molecular descriptors. The suitability of developed model was tested on β-blockers (n = 15). The model showed better prediction of corneal permeability for fluoroquinolones (r(2) > 0.9) as well as β-blockers (r(2) > 0.6). The newly developed QSPR model based upon in vivo generated data was found suitable to predict corneal permeability for fluoroquinolones as well as other sets of compounds.
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ItemNo Preview AvailableVisual outcome of cataract surgery with pupillary sphincterotomy in eyes with coexisting corneal opacity(BIOMED CENTRAL LTD, 2004)BACKGROUND: To evaluate the visual outcome following cataract surgery with pupillary sphincterotomy in eyes with coexisting corneal opacity. METHODS: Patients with leucomatous corneal opacity with significant cataract were enrolled for the study. The uncorrected visual acuity and best-corrected visual acuity (BCVA) were recorded and the anterior segment was thoroughly evaluated by a slit lamp biomicroscope before the surgery. Only those patients who had some amount of clear peripheral cornea were selected. Posterior segment pathology was ruled out by indirect ophthalmoscopy after pupillary dilatation, if possible, or by B-scan ultrasonography. Conventional extracapsular cataract extraction with pupillary sphincterotomy was performed and an intraocular lens was implanted. Postoperatively, the eyes were evaluated on day 1, and 1 week and 6 weeks following surgery for similar parameters. RESULTS: Fourteen eyes of 14 patients were included in the study, of which 13 (92.85%) patients were male. The mean age of the patients was 47.85 +/- 7.37 years. All the eyes had a dense central leucomatous corneal opacity. Twelve (85.71%) eyes had two or more quadrants of deep vascularisation. Sphincterotomy was performed mostly (71.42%) in the nasal or inferonasal quadrant. The intraocular lens was implanted in 13 (92.85%) eyes, and one (7.1%) eye was left aphakic due to the occurrence of a large posterior capsular tear. Preoperatively, all eyes had BCVA < 6/60. At 6 weeks after surgery, all eyes had BCVA >or= 6/60 and four (28.57%) eyes had BCVA >or= 6/18. The mean BCVA preoperatively in these eyes was 0.015 +/- 0.009, which changed to 0.249 +/- 0.102 at 6 weeks following surgery. CONCLUSIONS: Extracapsular cataract extraction and intraocular lens implantation with pupillary sphincterotomy provides ambulatory and useful vision to patients of cataract with coexisting central leucomatous corneal opacity.
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ItemCorneal topographic changes following retinal surgery.(Springer Science and Business Media LLC, 2004-08-03)BACKGROUND: To study the effect of retinal/ vitreoretinal surgeries on corneal elevations. METHODS: Patients who underwent retinal/ vitreoretinal surgeries were divided into 3 groups. Scleral buckling was performed in 11 eyes (Group 1). In 8 (25%) eyes, vitreoretinal surgery was performed along with scleral buckling (Group 2). In 12 eyes, pars plana vitrectomy was performed for vitreous hemorrhage (Group 3). An encircling element was used in all the eyes. The parameters evaluated were best-corrected visual acuity (BCVA), change in axial length, and corneal topographic changes on Orbscan topography system II, preoperative and at 12 weeks following surgery. RESULTS: There was a statistically significant increase in anterior corneal elevation in all the three groups after surgery (p = 0.003, p = 0.008 & p = 0.003 respectively). The increase in posterior corneal elevation was highly significant in all the three groups after surgery (p = 0.0000, p = 0.0001 & p = 0.0001 respectively). The increase in the posterior corneal elevation was more than the increase in the anterior elevation and was significant statistically in all the three groups (group I: p = 0.02; group II: p = 0.01; group III: p = 0.008). CONCLUSIONS: Retinal/ vitreoretinal surgeries cause a significant increase in the corneal elevations and have a greater effect on the posterior corneal surface.
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ItemBowman's layer transplantation: evidence to date(DOVE MEDICAL PRESS LTD, 2018)Surgical management of keratoconus (KC) has undergone a paradigm shift in the last two decades and component corneal transplantation technique of deep anterior lamellar keratoplasty has established itself as a modality of choice for management of advanced cases of KC. Every now and then, new minimalist modalities are being innovated for the management of KC. On the same lines, a new technique, Bowman's layer transplantation, for surgical management of moderate to advanced KC has been reported in recent years. The procedure has shown to be beneficial in reducing ectasia in advanced KC with minimal intraoperative and postoperative complications. In this review, we intend to describe available information and literature with reference to this new surgical technique - Bowman's layer transplantation.